Xymon Mailing List Archive search

parsing bug in hobbit-clients.cfg

list Henrik Størner
Mon, 22 Nov 2010 21:52:00 +0000 (UTC)
Message-Id: <iceom0$ucg$user-e356fad9864f@xymon.invalid>

In <user-00d3d129a26d@xymon.invalid> Elmar Heeb <user-49eb29db847d@xymon.invalid> writes:
On 11/19/2010 12:53 PM, Elmar Heeb wrote:
Suppose you have the following entry in hobbit-clients.cfg:

HOST=blog.example.com,example.com
PROC apache

then the PROC test will be ignored for example.com. If the two hosts are
reversed, i.e.

HOST=example.com,blog.example.com
PROC apache

then the PROC test will be done for both hosts. I tried with a few
variations on this and it appears that any later string in the comma
separated list will be ignored if it is a substring of a string that
appeared earlier. The same goes for EXHOSTS and probably most other
selectors.

This bug is present in at least versions 4.3.0 beta2 (from Debian
lenny-backports) and 4.2.0 (from Debian lenny).
I have narrowed down the bug to the namematch subroutine in lib/matching.c and attached a patch.
The old code (which is the same in 4.2.0 and the svn trunk version) indeed explains the wrong behaviour.  Lacking a preceeding comma as a guard character essentially made any non-comma character a negating match and not just an '!'.  The patch explicitly tests for ",%s," and ",!%s," and thus makes sure that a partial match cannot prevent a later full match.

Thank You for a very detailed bug-report. Providing a simple testcase
was especially helpful. I considered using your suggested patch, but
instead decided to rewrite the routine since this turned out to be a
cleaner/simpler solution. So fixed in rev 6598.


Regards,
Henrik